CN112862632B - Method and system for blending and burning coal in thermal power plant - Google Patents

Abstract

The invention relates to a method and a system for blending and burning coal in a thermal power plant, relating to the technical field of thermal power generation, comprising the following steps of a, determining a plurality of selectable blending and burning ratios according to the variety and the number of coal types to be distributed and the allowed number of running coal mills; b, determining unit power supply cost according to the unit heating value and the standard coal unit price of each coal type to be distributed; c, determining a pre-selection proportioning ratio according to the maximum load capacity and the sulfur content of the coal to be distributed; d, determining the execution proportioning ratio in the load interval according to the unit power supply cost of each preselected proportioning ratio; step e, blending coal and co-burning according to the execution blending burning ratios and the preset coal blending mode; f, detecting the sulfur content in the generated waste gas and generating a detection result, and detecting the load capacity and generating a detection result; and g, adjusting and correcting the executed proportioning ratio according to each generated detection result. The invention effectively improves the efficiency of blending and burning the coal.

Description

Method and system for blending and burning coal in thermal power plant

Technical Field

The invention relates to the technical field of thermal power generation, in particular to a method and a system for blending and burning coal in a thermal power plant.

Background

The distribution and combustion of the thermal power plant generally takes design of coal types as main materials, and the coal types are stable. In recent years, the price of fire coal is greatly increased, the fuel cost of enterprises is high, and in order to reduce the fuel cost, some power plants start to mix and burn a large amount of lignite with lower price and low-quality land-transported bituminous coal. Compared with the designed coal types, the lignite and low-quality land bituminous coal generally have the problems of low calorific value, high moisture and high ash content, and the calorific value of the economic coal types is about 4000 kilocalories per kilogram, wherein the total moisture content of the lignite is about 30 percent, and the ash content of the land-borne bituminous coal is more than 30 percent. Meanwhile, due to the continuous increase of the installed capacity of the whole country and the expansion of the proportion of wind power photovoltaics, the load rate of the thermal power plant unit often wanders at a low position, and powerful conditions are provided for the large-scale blending and burning of low-quality coal.

Although the economic coal type is low in price, the coal quality parameter of the economic coal type is greatly different from the designed coal type, so that the power supply coal consumption of the unit is increased, and the efficiency of the unit is reduced more if the blending combustion proportion is larger. With the decrease of the price of the dominant coal, the price advantage factor of the economic coal is not obvious any more, the economic problem of blending and burning the economic coal is increasingly prominent, and in the daily blending and burning process, the blending and burning scheme is generally determined according to the blending and burning experience, so that the accuracy is insufficient, and the efficiency is low.

With the increasing strictness of national environmental protection policies, the importance of unit environmental protection operation is equal to safe operation and economic operation, and becomes a problem which must be considered primarily in unit operation. The environmental protection operation of the unit is closely related to the blending combustion of the blended coal, and particularly the completion of the desulfurization environmental protection index is greatly dependent on the sulfur content of the coal as fired.

Therefore, how to improve the economical efficiency and efficiency of blending coal and burning on the basis of ensuring the qualified sulfur content of the coal as fired is a technical problem to be solved at present.

Disclosure of Invention

Therefore, the invention provides a method and a system for blending and burning coal in a thermal power plant, which are used for solving the problem of low blending and burning efficiency caused by the fact that the blending and burning ratio of coal cannot be accurately controlled in the prior art.

In order to achieve the above object, in one aspect, the present invention provides a method for blending coal in a thermal power plant, including:

step a, a proportioning module determines a plurality of selectable proportioning ratios according to the variety and the number of the coal types to be distributed and the allowed operating number of the coal mills;

b, the proportioning module determines the unit power supply cost of each alternative blending combustion ratio in a preset load interval according to the unit heating value and the standard coal unit price of each coal type to be distributed;

c, the proportioning module determines a plurality of preselected proportioning ratios in the preset load interval from the selectable proportioning ratios according to the maximum load capacity of the coal to be distributed under the selectable proportioning ratios and the sulfur content of the coal to be distributed;

d, the proportioning module determines the execution proportioning ratio in the load interval according to the unit power supply cost of each preselected proportioning ratio;

step e, the execution module carries out coal blending and burning according to each execution coal blending and burning ratio and a preset coal blending mode;

step f, detecting the sulfur content in the generated waste gas by a detection module after the time of mixed combustion T1 to generate a detection result, and detecting the load capacity after the time of mixed combustion T2 to generate a detection result, wherein T1 is less than T2;

step g, the adjusting module adjusts and corrects the executed blending combustion ratio according to each detection result generated by the detecting module;

in the step c, when the proportioning module selects the pre-selected proportioning ratio, the proportioning module selects the average sulfur content deltaS and the maximum load carrying capacity M of the coal in a single selectable proportioning ratio_{Maximum of}Respectively comparing the standard values with corresponding preset standard values, and judging according to comparison results:

when the delta S is less than or equal to the delta S1, judging that the optional blending ratio meets the requirement of sulfur content, and carrying out secondary judgment;

when Delta S is > [ Delta S1, judging that the optional burdening ratio can not be used as a pre-selected burdening ratio;

wherein, the Delta S1 is a preset standard value of sulfur content;

when the proportioning module carries out secondary judgment, M1 is set as a preset standard value of load carrying capacity,

when M is_{Maximum of}If the optional blending ratio is less than M1, judging that the optional blending ratio cannot be used as a pre-selected blending ratio;

when M is_{Maximum of}When the ratio is more than or equal to M1, the optional blending ratio is judged to be a pre-selected blending ratio;

step g1, when the adjusting module adjusts the executing proportioning ratio, the adjusting module compares the exhaust gas sulfur content Q detected by the detecting module with each preset exhaust gas sulfur content, and selects a corresponding proportioning adjusting coefficient according to the comparison result to adjust the executing proportioning ratio; step g2, when the adjusting module corrects the executing combustion mixture ratio, the adjusting module compares the load capacity M detected by the detecting module with each preset load capacity, and selects a corresponding mixture ratio correction coefficient according to the comparison result to correct the executing combustion mixture ratio; and g3, when the correction is completed, the adjusting module compares the proportion P' of the coal with the lowest sulfur content in the adjusted execution blending ratio with the proportion of the coal with the lowest sulfur content in each preset proportion, and selects corresponding blending compensation parameters according to the comparison result to compensate the execution blending ratio.

Further, in the step g1, when the adjusting module selects the ith preset blending ratio adjustment coefficient α i to adjust the executed blending ratio, i =1,2,3 is set, and the ratio of the coal with the lowest sulfur content in the adjusted executed blending ratio is P ', P' = P × α i is set, where P is the ratio of the coal with the lowest sulfur content in the executed blending ratio, where,

when Q1 is more than or equal to Q < Q2, the adjusting module selects alpha 1 to adjust the executing proportioning firing ratio;

when Q2 is more than or equal to Q < Q3, the adjusting module selects alpha 2 to adjust the executing proportioning firing ratio;

when Q3 is not more than Q, the adjusting module selects alpha 3 to adjust the executing proportioning ratio;

wherein Q1 is the first preset exhaust gas sulfur content, Q2 is the second preset exhaust gas sulfur content, Q3 is the third preset exhaust gas sulfur content, Q1 is more than Q2 and more than Q3; alpha 1 is a first preset ratio adjusting coefficient, alpha 2 is a second preset ratio adjusting coefficient, alpha 3 is a third preset ratio adjusting coefficient, and alpha 1 is more than 1 and more than alpha 2 and more than alpha 3 and less than 2.

Further, in the step g2, when the adjusting module selects the i-th preset blending ratio correction coefficient β i to correct the execution blending ratio, i =1,2,3 is set, and the percentage of the coal with the highest calorific value in the corrected execution blending ratio is R ', R' = R × β i is set, where R is the percentage of the coal with the highest calorific value in the execution blending ratio,

when M1 is more than or equal to M < M2, the adjusting module selects beta 1 to correct the executed proportioning ratio;

when M2 is more than or equal to M < M3, the adjusting module selects beta 2 to correct the executed proportioning ratio;

when M3 is less than or equal to M, the adjusting module selects beta 3 to correct the executing combustion mixture ratio;

wherein M1 is a first preset load carrying capacity, M2 is a second preset load carrying capacity, M3 is a third preset load carrying capacity, M1 is more than M2 is more than M3; beta 1 is a first preset ratio correction coefficient, beta 2 is a second preset ratio correction coefficient, beta 3 is a third preset ratio correction coefficient, and beta 1 is more than 1 and more than beta 2 and more than beta 3 and less than 2;

in the step g3, when the adjusting module selects the i-th preset blending ratio compensation parameter θ i to compensate the executed blending ratio, i =1,2,3 is set, the percentage of the coal with the highest calorific value in the compensated executed blending ratio is R ", R" = R' × θ i is set, wherein,

when P' < P1, the adjusting module selects theta 1 to compensate the executed proportioning ratio;

when P1 is not less than P' < P2, the adjusting module selects theta 2 to compensate the executed proportioning ratio;

when P2 is not less than P' < P3, the adjusting module selects theta 3 to compensate the executed proportioning ratio;

wherein P1 is the coal proportion with the lowest first preset sulfur content, P2 is the coal proportion with the lowest second preset sulfur content, P3 is the coal proportion with the lowest third preset sulfur content, and P1 is more than P2 and more than P3; theta 1 is a first preset ratio compensation parameter, theta 2 is a second preset ratio compensation parameter, theta 3 is a third preset ratio compensation parameter, and theta 1 is more than 0 and more than theta 2 and more than theta 3 and less than 1.

Further, in the step b, when the proportioning module determines the unit power supply cost,

the proportioning module determines the calorific value of the coal as fired corresponding to each selectable proportioning ratio according to the calorific value;

the proportioning module determines power supply coal consumption corresponding to each load interval according to each coal as fired calorific value;

the proportioning module determines the unit price of coal as fired corresponding to each optional proportioning ratio according to the unit price of the standard coal;

and the proportioning module determines the unit power supply cost according to the power supply coal consumption and the unit coal as fired unit price.

Further, the calculation formula of the power supply coal consumption is as follows,

b_{for supplying to}=a₀+a₁M³+a₂M²+a₃M+a₄+b₁N²+b₂N+b₃

Wherein, b_{For supplying to}For the supply of power, a₀Rated load power supply coal consumption for units in the design of coal type for combustion, a₁、a₂、a₃、a₄For a first set of predetermined constants, b₁、b₂、b₃And the second group of preset constants, M is the unit load, and N is the calorific value of the coal as fired.

Further, in the step c, the proportioning module, when determining the pre-selected proportioning ratio,

determining the sulfur content of the coal as fired corresponding to each optional co-firing ratio according to the sulfur content;

and determining the selectable co-firing ratio of which the maximum load carrying capacity meets the load interval and the sulfur content of each coal as fired is less than or equal to a preset threshold value as the pre-selected co-firing ratio.

Further, the maximum load capacity is calculated by the formula,

M_{maximum of}=D×W/ b_{For supplying to}(1-n)×7000/ N/10^3

Wherein M is_{Maximum of}For the maximum load capacity, D is the maximum coal amount of a single mill, W is the number of running coal mills, b_{For supplying to}And N is the plant power consumption of the unit and the calorific value of the coal as fired.

Further, in the step d, the load interval is determined after the load range of the generator set is divided according to a preset load limit value, the load interval includes a high load interval, a medium load interval and a low load interval, when the proportioning module determines the executing proportioning ratio,

if the coal types to be distributed are a group, taking the preselected combustion ratio with the minimum unit power supply cost in the high load interval as the optimal combustion ratio of the high load interval, taking the preselected combustion ratio which is matched with the optimal combustion ratio of the high load interval and has the minimum unit power supply cost in the intermediate load interval as the optimal combustion ratio of the intermediate load interval, taking the preselected combustion ratio which is matched with the optimal combustion ratio of the high load interval and the optimal combustion ratio of the intermediate load interval and has the minimum unit power supply cost in the low load interval as the optimal combustion ratio of the low load interval, and taking the optimal combustion ratio of the high load interval, the optimal combustion ratio of the intermediate load interval and the optimal combustion ratio of the low load interval as the execution combustion ratio;

if the number of the coal types to be distributed is more than one, determining the comprehensive unit power supply cost of each group of the coal types to be distributed according to the proportion of the generated energy of each load interval in the preset time length in the future and the unit power supply cost under each optimal distribution ratio corresponding to each group of the coal types to be distributed, and determining each executing distribution ratio according to each optimal distribution ratio of the coal types to be distributed with the minimum comprehensive unit power supply cost or each optimal distribution ratio of the coal types to be distributed corresponding to a selection instruction input by a user.

Further, the calculation formula of the integrated unit power supply cost is as follows,

G_{synthesis of}=C_{Height of}×G_{Height of}+C_In×G_In+C_{Is low in}×G_{Is low in}

Wherein G is_{Synthesis of}Cost of power supply to said integrated unit, C_{Height of}Unit power supply cost, G, for optimal firing ratio in high load intervals_{Height of}Is the proportion of the power generation in the high load region, C_InUnit power supply cost, G, for optimal firing ratio between medium load regions_InIs the proportion of the power generation in the medium load region, C_{Is low in}Unit power supply cost, G, for optimal firing ratio in low load region_{Is low in}Is a proportion of the amount of power generation in the low load section.

On the other hand, the invention also provides a system for blending and burning coal in a thermal power plant, which comprises the following components:

the proportioning module is used for determining the executing proportioning ratio of the coal blending combustion and is connected with the executing module;

the execution module is used for carrying out coal blending and burning according to each execution blending and burning ratio and a preset coal blending mode and is connected with the detection module;

the detection module is used for detecting the sulfur content and the load capacity in the waste gas and generating a corresponding detection result, and is connected with the adjustment module;

and the adjusting module is used for adjusting and correcting the executed combustion allocation ratio according to each detection result generated by the detecting module.

Compared with the prior art, the invention has the advantages that the matching module determines the selectable matching combustion ratio according to the type quantity of the coal to be distributed and the allowed operation number of the coal mills, the accuracy of the selectable matching ratio is effectively improved, the matching module determines a plurality of pre-selection matching combustion ratios according to the maximum load capacity of the coal to be distributed under each selectable matching combustion ratio and the sulfur content of each coal to be distributed, the accuracy of the pre-selection matching combustion ratio is effectively improved, the matching module determines the execution matching combustion ratio according to the unit power supply cost of each pre-selection matching combustion ratio, the accuracy of the execution matching combustion ratio is effectively improved, the matching combustion cost is saved, the efficiency of the blending coal blending combustion is further improved, the adjustment module adjusts the execution matching combustion ratio according to the sulfur content Q of the waste gas detected by the detection module, and the accuracy of the execution matching combustion ratio is further improved, the coal blending and burning efficiency is further improved, the adjusting module corrects the executing blending and burning ratio according to the load capacity M detected by the detecting module, the accuracy of executing the blending and burning ratio is further improved, and the coal blending and burning efficiency is further improved.

Particularly, when the proportioning module determines the executing proportioning ratio, the proportioning module determines the executing proportioning ratio according to different optimal proportioning ratios of different quantities of coal, so that the accuracy of the executing proportioning ratio is further improved, and the efficiency of the blending and burning of the blended coal is further improved.

Particularly, the proportioning module calculates the comprehensive unit power supply cost according to a calculation formula of the comprehensive unit power supply cost, so that the accuracy of the comprehensive unit power supply cost is effectively improved, the accuracy of the execution proportioning and burning ratio is further improved, and the efficiency of the coal blending and burning is further improved.

Particularly, the proportioning module determines each unit power supply cost according to the power supply coal consumption and the unit coal as fired unit price, so that the accuracy of the unit power supply cost is effectively guaranteed, the accuracy of the execution proportioning and burning ratio is further improved, and the efficiency of the proportioning and burning is further improved.

Particularly, the proportioning module calculates the power supply coal consumption according to a calculation formula, so that the accuracy of the power supply coal consumption is effectively ensured, the accuracy of unit power supply cost is further improved, the accuracy of executing the blending combustion ratio is further improved, and the efficiency of blending coal and burning is further improved.

In particular, the proportioning module determines the pre-selection proportioning ratio according to the maximum load capacity and the sulfur content of the coal as fired, so that the accuracy of the pre-selection proportioning ratio is effectively ensured, the accuracy of executing the proportioning ratio is further improved, and the efficiency of blending and burning the coal is further improved.

Particularly, the proportioning module calculates the maximum loaded capacity according to a calculation formula, so that the accuracy of pre-selecting the proportioning and burning ratio is further improved, the accuracy of executing the proportioning and burning ratio is further improved, and the efficiency of blending and burning the coal is further improved.

Particularly, the adjusting module compares the sulfur content Q of the waste gas detected by the detecting module with the sulfur content of each preset waste gas, and selects a corresponding proportion adjusting coefficient according to the comparison result to adjust the executing proportion combustion ratio, so that the accuracy of executing the proportion combustion ratio is further improved, and the efficiency of blending coal and burning is further improved.

Particularly, the adjusting module compares the load capacity M detected by the detecting module with each preset load capacity, and selects a corresponding proportion correction coefficient according to the comparison result to correct the executing proportion combustion ratio, so that the accuracy of executing the proportion combustion ratio is further improved, and the efficiency of blending coal is further improved.

Drawings

FIG. 1 is a schematic flow chart of a coal blending co-combustion method in a thermal power plant according to the present embodiment;

fig. 2 is a schematic diagram of a framework of the coal blending and co-combustion system of the thermal power plant in this embodiment.

Detailed Description

In order that the objects and advantages of the invention will be more clearly understood, the invention is further described below with reference to examples; it should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

Preferred embodiments of the present invention are described below with reference to the accompanying drawings. It should be understood by those skilled in the art that these embodiments are only for explaining the technical principle of the present invention, and do not limit the scope of the present invention.

It should be noted that in the description of the present invention, the terms of direction or positional relationship indicated by the terms "upper", "lower", "left", "right", "inner", "outer", etc. are based on the directions or positional relationships shown in the drawings, which are only for convenience of description, and do not indicate or imply that the device or element must have a specific orientation, be constructed in a specific orientation, and be operated, and thus, should not be construed as limiting the present invention.

Furthermore, it should be noted that, in the description of the present invention, unless otherwise explicitly specified or limited, the terms "mounted," "connected," and "connected" are to be construed broadly, and may be, for example, fixedly connected, detachably connected, or integrally connected; can be mechanically or electrically connected; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meanings of the above terms in the present invention can be understood by those skilled in the art according to specific situations.

Referring to fig. 1, a method for blending coal in a thermal power plant according to the present invention includes:

step a, a proportioning module determines a plurality of selectable proportioning ratios according to the variety and the number of the coal types to be distributed and the allowed operating number of the coal mills;

b, the proportioning module determines the unit power supply cost of each alternative blending combustion ratio in a preset load interval according to the unit heating value and the standard coal unit price of each coal type to be distributed;

c, the proportioning module determines a plurality of preselected proportioning ratios in the preset load interval from the selectable proportioning ratios according to the maximum load capacity of the coal to be distributed under the selectable proportioning ratios and the sulfur content of the coal to be distributed;

d, the proportioning module determines the execution proportioning ratio in the load interval according to the unit power supply cost of each preselected proportioning ratio;

step e, the execution module carries out coal blending and burning according to each execution coal blending and burning ratio and a preset coal blending mode;

step f, detecting the sulfur content in the generated waste gas by a detection module after the time of mixed combustion T1 to generate a detection result, and detecting the load capacity after the time of mixed combustion T2 to generate a detection result, wherein T1 is less than T2;

and g, adjusting and correcting the executed blending combustion ratio by an adjusting module according to each detection result generated by the detecting module.

Specifically, in the step c, when the proportioning module selects the pre-selected proportioning ratio, the proportioning module selects the average sulfur content Δ S and the maximum load carrying capacity M of the coal in the single selectable proportioning ratio_{Maximum of}Respectively comparing the standard values with corresponding preset standard values, and judging according to comparison results:

when the delta S is less than or equal to the delta S1, judging that the optional blending ratio meets the requirement of sulfur content, and carrying out secondary judgment;

when Delta S is > [ Delta S1, judging that the optional burdening ratio can not be used as a pre-selected burdening ratio;

wherein, the Delta S1 is a preset standard value of sulfur content;

when the proportioning module carries out secondary judgment, M1 is set as a preset standard value of load carrying capacity,

when M is_{Maximum of}If the optional blending ratio is less than M1, judging that the optional blending ratio cannot be used as a pre-selected blending ratio;

when M is_{Maximum of}And when the mass ratio is more than or equal to M1, judging that the optional batch burning ratio can be used as a pre-selected batch burning ratio.

Specifically, the step g includes a step g1, where when the adjusting module adjusts the executing proportioning ratio, the adjusting module compares the exhaust gas sulfur content Q detected by the detecting module with each preset exhaust gas sulfur content, and selects a corresponding proportioning adjusting coefficient according to a comparison result to adjust the executing proportioning ratio; step g2, when the adjusting module corrects the executing combustion mixture ratio, the adjusting module compares the load capacity M detected by the detecting module with each preset load capacity, and selects a corresponding mixture ratio correction coefficient according to the comparison result to correct the executing combustion mixture ratio; and g3, when the correction is completed, the adjusting module compares the proportion P' of the coal with the lowest sulfur content in the adjusted execution blending ratio with the proportion of the coal with the lowest sulfur content in each preset proportion, and selects corresponding blending compensation parameters according to the comparison result to compensate the execution blending ratio.

Specifically, in the step b, when the proportioning module determines the unit power supply cost,

the proportioning module determines the calorific value of the coal as fired corresponding to each selectable proportioning ratio according to the calorific value;

the proportioning module determines power supply coal consumption corresponding to each load interval according to each coal as fired calorific value;

the proportioning module determines the unit price of coal as fired corresponding to each optional proportioning ratio according to the unit price of the standard coal;

and the proportioning module determines the unit power supply cost according to the power supply coal consumption and the unit coal as fired unit price.

Specifically, in order to determine the accurate calorific value of the coal as fired, in the embodiment of the present application, the coal types to be allocated include the coal type 1 and the coal type 2, and the calorific value of the coal as fired N = KN_{Coal type 1}+（1-K）N_{Coal type 2}K is the proportion of 1 type of coal in the optional blending ratio, N_{Coal type 1}The calorific value of coal type 1, N_{Coal type 2}Is the calorific value of the coal type 2.

Specifically, in order to accurately determine the unit price of coal as fired, in the embodiment of the present application, the coal types to be distributed include coal type 1 and coal type 2, and the unit price of coal as fired B_{Coal as fired}=（K×N_{Coal type 1}×B_{Coal type 1} +（1-K）×N_{Coal type 2}×B_{Coal type 2}）/（K×N_{Coal type 1}+（1-K）×N_{Coal type 2}) Wherein K is the proportion of 1 coal type in the optional blending combustion ratio, N_{Coal type 1}The calorific value of coal type 1, N_{Coal type 2}The calorific value of coal type 2, B_{Coal type 1}Standard coal unit price for coal type 1, B_{Coal type 2}The standard coal unit price of the coal type 2.

Specifically, the proportioning module determines each unit power supply cost according to the power supply coal consumption and the unit coal as fired unit price, so that the accuracy of the unit power supply cost is effectively guaranteed, the accuracy of the execution proportioning and burning ratio is further improved, and the efficiency of the proportioning and burning is further improved.

Specifically, the calculation formula of the power supply coal consumption is as follows,

b_{for supplying to}=a₀+a₁M³+a₂M²+a₃M+a₄+b₁N²+b₂N+b₃

Wherein, b_{For supplying to}For the supply of power, a₀Rated load power supply coal consumption for units in the design of coal type for combustion, a₁、a₂、a₃、a₄For a first set of predetermined constants, b₁、b₂、b₃And the second group of preset constants, M is the unit load, and N is the calorific value of the coal as fired.

In this embodiment, historical report data of performance tests of each unit and actual operating parameters of the units in the SIS system may be input into origin software to perform analysis fitting on the selected parameters, and coefficients a1, a2, a3, a4, b1, b2, and b3 in formula three may be determined.

Specifically, in the step c, the proportioning module, when determining the pre-selected proportioning ratio,

determining the sulfur content of the coal as fired corresponding to each optional co-firing ratio according to the sulfur content;

and determining the selectable co-firing ratio of which the maximum load carrying capacity meets the load interval and the sulfur content of each coal as fired is less than or equal to a preset threshold value as the pre-selected co-firing ratio.

Specifically, in order to accurately determine the sulfur content of the coal as fired, in the examples of the present application, the coal types to be distributed include coal type 1 and coal type 2, and the sulfur content of the coal as fired S = (KS)_{Coal type 1}+ (1-K)S_{Coal type 2}) /100, wherein K is an optional match burning ratioProportion of 1 kind of medium coal, S_{Coal type 1}Sulfur content, S, of coal type 1_{Coal type 2}The sulfur content of coal 2.

Specifically, the proportioning module determines the pre-selection proportioning ratio according to the maximum load capacity and the sulfur content of the coal as fired, so that the accuracy of the pre-selection proportioning ratio is effectively ensured, the accuracy of executing the proportioning ratio is further improved, and the efficiency of blending and burning the coal is further improved.

Specifically, the maximum load capacity is calculated by the formula,

M_{maximum of}=D×W/ b_{For supplying to}(1-n)×7000/ N/10^3

Wherein M is_{Maximum of}For the maximum load capacity, D is the maximum coal amount of a single mill, W is the number of running coal mills, b_{For supplying to}And N is the plant power consumption of the unit and the calorific value of the coal as fired.

Specifically, in the step d, the load interval is determined after the load range of the generator set is divided according to a preset load limit value, the load interval includes a high load interval, a medium load interval and a low load interval, and when the proportioning module determines the combustion ratio,

if the coal types to be distributed are a group, taking the preselected combustion ratio with the minimum unit power supply cost in the high load interval as the optimal combustion ratio of the high load interval, taking the preselected combustion ratio which is matched with the optimal combustion ratio of the high load interval and has the minimum unit power supply cost in the intermediate load interval as the optimal combustion ratio of the intermediate load interval, taking the preselected combustion ratio which is matched with the optimal combustion ratio of the high load interval and the optimal combustion ratio of the intermediate load interval and has the minimum unit power supply cost in the low load interval as the optimal combustion ratio of the low load interval, and taking the optimal combustion ratio of the high load interval, the optimal combustion ratio of the intermediate load interval and the optimal combustion ratio of the low load interval as the execution combustion ratio;

if the number of the coal types to be distributed is more than one, determining the comprehensive unit power supply cost of each group of the coal types to be distributed according to the proportion of the generated energy of each load interval in the preset time length in the future and the unit power supply cost under each optimal distribution ratio corresponding to each group of the coal types to be distributed, and determining each executing distribution ratio according to each optimal distribution ratio of the coal types to be distributed with the minimum comprehensive unit power supply cost or each optimal distribution ratio of the coal types to be distributed corresponding to a selection instruction input by a user.

Specifically, for example, the coal to be distributed includes coal 1 and coal 2, the unit has five coal mills, and if the optimal blending-burning ratio in the high-load interval is 3:1, 4 coal mills 1, 1 coal mill 2 or 3 coal mills 1,2 coal mills 2 are needed; the optimal match burning ratio between the medium load areas is a pre-selected match burning ratio which is matched with 3:1 and has the minimum unit power supply cost, such as 2:2, and cannot be 1:3 or 0:4, because the coal 2 enters two mills at most, 3 mills are needed to grind the coal 1, and 2 mills are needed to grind the coal 2; similarly, the optimal match-burning ratio in the low-load interval is a pre-selected match-burning ratio which is matched with 3:1 and 2:2 and has the minimum unit power supply cost, such as 2:2, and cannot be 1:3 or 0:4 or 4:0, because 3 mills are used for grinding coal 1 and 2 mills are used for grinding coal 2, so that the optimal match-burning ratio in the high-load interval and the medium-load interval is met simultaneously.

Specifically, the comprehensive unit power supply cost of each group of coal types to be distributed is determined according to the proportion of the power generation amount of each load interval in the future preset time and the unit power supply cost under each optimal power distribution ratio corresponding to each group of coal types to be distributed, the future preset time can be one day or two days in the future, and the proportion of the power generation amount of each load interval can be determined according to the data of the previous day automatically counted by the SIS system; when the proportion of high, medium and low loads of the unit in the future day is possibly greatly different from the proportion of loads in each section in the previous day due to sudden change of wind power load on the network, or load change on the network in holidays or faults of the network or the unit, the proportion of the generated energy in each load section can be determined according to the proportion input by a user.

Specifically, the calculation formula of the integrated unit power supply cost is as follows,

G_{synthesis of}=C_{Height of}×G_{Height of}+C_In×G_In+C_{Is low in}×G_{Is low in}

Wherein G is_{Synthesis of}Cost of power supply to said integrated unit, C_{Height of}Unit power supply cost, G, for optimal firing ratio in high load intervals_{Height of}Is the proportion of the power generation in the high load region, C_InUnit power supply cost, G, for optimal firing ratio between medium load regions_InIs the proportion of the power generation in the medium load region, C_{Is low in}Unit power supply cost, G, for optimal firing ratio in low load region_{Is low in}Is a proportion of the amount of power generation in the low load section.

Specifically, in this embodiment, the number of the types is two, the preset coal blending mode is a single type of coal on each coal bunker, the coal amount of each coal mill is the same, and the coal blending is performed according to each executed blending ratio and the preset coal blending mode, specifically,

and coal is fed to each coal bunker according to each execution proportioning ratio and the preset coal blending mode, and a coal mill corresponding to each execution proportioning ratio is operated in each load interval.

In the embodiment, each mixed combustion scheme only comprises two coal types, the site can be vacated as soon as possible when the capacity of the coal yard is not large, preparation is made for next batch of coal to enter the plant, and the two coal types are mixed and combusted at each time, so that convenience in warehousing, operation adjustment and economic analysis is facilitated. Each coal type is loaded in a single bin and is combusted in the furnace, and the coal quantity of the running coal mills is the same. When the unit load changes, the blending proportion of the economic coal is changed by reverse grinding, so as to achieve the purpose of maximizing the blending benefit.

Specifically, the single-bin coal feeding and the furnace internal combustion not only stabilize the unit parameters, but also avoid the condition of higher carbon content of fly ash caused by grinding and furnace charging of different coal types in the same pulverizing system. Another benefit of single-bin coal charging is that the blending of the economical coal blending proportion is rapid, and the reverse grinding is generally completed within half an hour. Because of the influence of factors such as grid peak-valley change, wind-powered electricity generation, circuit trouble, the unit load is the difference of height in the middle of the day, and the uncertainty is great moreover, consequently, changes the unit load that not only quick response has been put to the formula of burning through the mode of grinding backward, can make the formula of burning benefit maximize moreover.

The coal quantity of the coal mills in operation is the same, so that the load response speed of the unit is high, and if the coal pulverizing system has no influence on the output problem, the coal quantity of all the coal mills in operation is generally the same.

Specifically, in order to improve the blending combustion efficiency, the preset coal blending mode is to layer coal on each coal bunker, and the blending combustion is carried out according to each execution blending combustion ratio and the preset coal blending mode, specifically,

determining the amount of coal charged into the furnace of each load interval according to the generated energy, the generated coal consumption and the heat productivity of each coal type to be distributed in each load interval within the future preset time;

determining the coal feeding type and the coal feeding amount of each load interval according to the execution blending ratio and the coal feeding amount;

and according to the coal feeding type and the coal feeding amount, feeding coal to each coal bunker layer by layer, and operating a coal mill corresponding to each executed blending combustion ratio in each load interval.

In the embodiment, the power grid load in the future preset time can be predicted by sampling, learning and training the power grid data, the coal charging amount of each load interval is determined according to the generated energy, the generated coal consumption and the calorific value of each coal type to be distributed in the future preset time, the coal charging type and the coal charging amount of each load interval are determined according to the execution blending ratio and the coal charging amount, the coal charging is performed, and the coal mill corresponding to each execution blending ratio is operated in each load interval.

By layering and feeding coal to each coal bunker, the coal blending quality and the coal quantity under the target load can be controlled, a coal mill does not need to be replaced when the load changes, and the coal blending combustion rate of the coal as fired is further improved.

In order to reliably determine the coal charge amount of each load interval, in some embodiments of the present application, the coal charge amount of each load interval a = V × b × 7000/N/10^6, where V is the power generation amount of each load interval, b is the power generation coal consumption of each load interval, N is the coal charge heating value, and N = KN_{Coal type 1}+（1-K）N_{Coal type 2}. The coal types to be distributed comprise coal type 1 and coal type 2, the coal charging amount of the coal type 1 and the coal type 2 is determined according to the coal charging amount A, the coal charging amount A1= A x K of the coal type 1, and the coal charging amount A2= A x (1-K) of the coal type 2.

Specifically, in the step g1, when the adjusting module selects the i-th preset blending ratio adjustment coefficient α i to adjust the executing blending ratio, i =1,2,3 is set, and the percentage of the coal with the lowest sulfur content in the adjusted executing blending ratio is P ', P' = P × α i is set, where P is the percentage of the coal with the lowest sulfur content in the executing blending ratio, where,

when Q1 is more than or equal to Q < Q2, the adjusting module selects alpha 1 to adjust the executing proportioning firing ratio;

when Q2 is more than or equal to Q < Q3, the adjusting module selects alpha 2 to adjust the executing proportioning firing ratio;

when Q3 is not more than Q, the adjusting module selects alpha 3 to adjust the executing proportioning ratio;

wherein Q1 is the first preset exhaust gas sulfur content, Q2 is the second preset exhaust gas sulfur content, Q3 is the third preset exhaust gas sulfur content, Q1 is more than Q2 and more than Q3; alpha 1 is a first preset ratio adjusting coefficient, alpha 2 is a second preset ratio adjusting coefficient, alpha 3 is a third preset ratio adjusting coefficient, and alpha 1 is more than 1 and more than alpha 2 and more than alpha 3 and less than 2.

Specifically, in the step g2, when the adjustment module selects the i-th preset blending ratio correction coefficient β i to correct the execution blending ratio, i =1,2,3 is set, and the percentage of the coal having the highest calorific value among the corrected execution blending ratios is R ', R' = R × β i is set, where R is the percentage of the coal having the highest calorific value among the execution blending ratios,

when M1 is more than or equal to M < M2, the adjusting module selects beta 1 to correct the executed proportioning ratio;

when M2 is more than or equal to M < M3, the adjusting module selects beta 2 to correct the executed proportioning ratio;

when M3 is less than or equal to M, the adjusting module selects beta 3 to correct the executing combustion mixture ratio;

wherein M1 is a first preset load carrying capacity, M2 is a second preset load carrying capacity, M3 is a third preset load carrying capacity, M1 is more than M2 is more than M3; beta 1 is a first preset ratio correction coefficient, beta 2 is a second preset ratio correction coefficient, beta 3 is a third preset ratio correction coefficient, and beta 1 is more than 1 and more than beta 2 and more than beta 3 and less than 2.

Specifically, in the step g3, when the adjusting module selects the i-th preset blending ratio compensation parameter θ i to compensate the executed blending ratio, i =1,2,3 is set, and the percentage of the coal with the highest calorific value in the compensated executed blending ratio is R ″ = R' × θ i, where,

when P' < P1, the adjusting module selects theta 1 to compensate the executed proportioning ratio;

when P1 is not less than P' < P2, the adjusting module selects theta 2 to compensate the executed proportioning ratio;

when P2 is not less than P' < P3, the adjusting module selects theta 3 to compensate the executed proportioning ratio;

wherein P1 is the coal proportion with the lowest first preset sulfur content, P2 is the coal proportion with the lowest second preset sulfur content, P3 is the coal proportion with the lowest third preset sulfur content, and P1 is more than P2 and more than P3; theta 1 is a first preset ratio compensation parameter, theta 2 is a second preset ratio compensation parameter, theta 3 is a third preset ratio compensation parameter, and theta 1 is more than 0 and more than theta 2 and more than theta 3 and less than 1.

Specifically, the adjusting module compares the load capacity M detected by the detecting module with each preset load capacity, and selects a corresponding proportion correction coefficient according to the comparison result to correct the executing proportion combustion ratio, so that the accuracy of executing the proportion combustion ratio is further improved, and the efficiency of blending coal is further improved.

In order to further illustrate the technical idea of the present invention, the technical solution of the present invention will now be described with reference to specific application scenarios.

The embodiment of the invention provides a benefit blending combustion model based on the method for blending coal and combusting in a thermal power plant, wherein each blending combustion scheme of the benefit blending combustion model only comprises two coal types, the preset coal blending mode is that a single coal type is arranged on each coal bunker, and the coal amount of each coal mill is the same.

1. Before operating the benefit combustion mixture model, firstly, the parameters of the combustion mixture model need to be configured, as shown in table 1, including:

TABLE 1

(1) Maximum load parameter configuration

The maximum load parameter may be configured in the range of 300MW to 350MW, typically 350MW, but the maximum load parameter setting may be changed if it is determined that the unit is not required to carry full load (e.g. the unit load is limited due to grid line reasons, etc.).

(2) Configuration of sulfur content parameter of coal as fired

The sulfur content parameter configuration target of the coal as fired is to meet the requirement of unit environmental protection emission index, and can be changed according to factors such as season, environmental protection equipment condition, heating surface corrosion condition and the like, and the sulfur content of the comprehensive coal as fired after the configuration combustion is set to be not more than 1%.

(3) Maximum coal quantity parameter configuration of single mill

The maximum coal amount of the unit is generally configured by considering the maximum coal amount of the unit, for example, if the maximum coal amount of the unit is limited due to the output of a wind and smoke system caused by the blockage of an air preheater, a denitration reactor and an absorption tower or the output of the wind and smoke system is reduced due to the rise of the weather temperature, the maximum coal amount of the unit cannot exceed a certain value, and at the moment, the maximum coal amount of the unit can be configured by the single mill, so that the configuration scheme can meet the output requirement of the wind and smoke system of the unit. For example, the maximum coal amount of a unit in the first period is designed to be 160 tons/hour, the maximum coal amount of a single mill is 40 tons/hour, the output of a wind and smoke system is limited due to some reason, the maximum coal amount of the unit can only reach 150 tons/hour, otherwise, the positive pressure of a hearth can be caused, and the maximum coal amount of the single mill can be modified to be 37.5 tons/hour.

(4) High, medium and low load ratio parameter configuration

The high, medium and low load proportion parameters generally adopt the proportion of high, medium and low load of the unit in the previous day which is automatically counted by an SIS system as the proportion of each section of the unit load in the next day, and the change-over switch value is 1 at the moment. When the change-over switch value is manually changed to '0', the load proportion of each section of the unit in the future day can be manually recorded, and the load proportion is recorded manually when the load proportion of the unit in the future day is possibly greatly different from the load proportion of each section in the previous day due to sudden change of wind power load on the network, or load change on the network in holidays or faults of circuits or units on the network.

(5) Coal quality parameter configuration

The name, calorific value, sulfur content, volatile matter, ash, external moisture, standard coal unit price and the economic coal type mark of the existing coal types in the coal yard are added into the coal quality parameter area in the configuration table. (volatile matter, ash and external moisture are only used as reference and do not participate in calculation)

(6) Other parameter configuration

In addition to the configuration parameters, the daily average temperature is also required to be configured in consideration of external heat supply of the winter units; in order to predict the amount of coal charged in the furnace in the tomorrow and the next month, the number of the current units, the predicted number of units in the next month and the next month planned electric quantity parameter are input; because the heat supply in winter influences, the model operation mode is different from the pure condensation operation mode of the summer unit, and therefore a 'pure condensation/heat supply' switching button is arranged; when the next month fire coal purchase prediction is carried out, because the calculated amount is large and the model operation speed is low, a monthly prediction button is arranged, when the monthly prediction is not carried out, the button is closed, the operation in the monthly prediction aspect is not carried out, and the model operation speed can be improved.

2. After the configuration of the parameters of the benefit combustion allocation model is finished, model operation is carried out, and a benefit combustion allocation scheme sorting table is obtained according to the comprehensive unit power supply cost of each group of coal types to be allocated, as shown in table 2;

TABLE 2

The multiple blending burning schemes are ranked according to the economic merits, and the more advanced blending burning scheme has better economic performance. Each combustion allocation scheme gives parameters such as specific coal type information, combustion allocation proportion of each load interval, sulfur content of coal as fired in each load interval, actual maximum load of each load interval, comprehensive heat productivity of coal as fired in each load interval and the like. Wherein, the coal mill combination of two kinds of coal in each load interval can be obtained from the proportioning and burning proportion, and the reverse grinding time can be known from the actual maximum load of each load interval.

As shown in table 2, the two coals in the No. 1 co-firing schedule were S2014032 australian coal and L14159 batch terrestrially-transported bituminous coal, respectively. According to the blending and burning proportion, three milling bins S2014032 ship Australian coal in five coal mills of the first unit, and two milling bins L14151 transport bituminous coal on land in batches. When the unit load is below 300MW, the blending combustion ratio is 2:2, and the running mills are two S2014032 ship Australian coal mills and two L14159 batch land-transported bituminous coal mills respectively; when the load of the unit exceeds 300MW and the continuous load increase of the unit is judged according to the online load and the operation experience, combining the coal mills into three S2014032 ship Australian coal mills and one L14159 batch land transportation coal mill for operation; similarly, when the unit load is reduced to 300MW from full load, the unit is judged to continuously reduce the load according to the online load and the operation experience, and at the moment, the coal mill combination is changed into the operation of two S2014032 ship Australia coal mills and two L14159 batches of terrestrially transported bituminous coal mills from the combination of three S2014032 ship Australia coal mills and one L14159 batch of terrestrially transported bituminous coal mills.

However, when the combined combustion scheme is actually selected, the No. 1 combined combustion scheme is not necessarily selected, and the previous combined combustion schemes may not meet the actual requirements, for example, when the above-mentioned restriction conditions of old and new coal burning requirements of a coal yard, a coal yard emptying requirement, the influence of coal pulverizing system equipment maintenance and the like exist, the combined combustion scheme can be selected from top to bottom according to the actual situation. For example, if the coal of Oudou Kanto 2014030 is overheated due to long storage time and needs to be charged into the furnace as soon as possible, the No. 5 blending scheme can be sequentially selected, i.e., the coal of Oudou Kanto 2014030 and the bituminous coal of L14151 batch are blended and combusted. When the coal of Dayou ship or L14151 is burnt, the optimal proportioning scheme meeting the conditions can be selected again.

3. Reference to procurement of coal

Besides inputting the existing coal type information in the coal yard into the blending combustion model for calculation, the coal type information which is not available in the coal yard but has been burnt can be input into the blending combustion model for calculation together with the existing coal type information in the coal yard, and the coal type which is ranked in the top in the blending combustion scheme is selected for purchase and acquisition in the plant.

Even if some coal types are never burnt, the coal types can be put into the furnace for proportioning from the coal parameters, the coal information and the price can also be input into the proportioning model for operation, if the coal types are ranked at the front in the proportioning scheme, a small amount of trial burning can be purchased in the plant, and whether the large amount of coal types are continuously purchased in the plant is judged according to the trial burning result.

4. Reference to quantity of coal purchased

If the type of coal to be purchased in the next month is determined, the purchase amount can be estimated through a co-firing model, which is exemplified below.

Such as: if the optimal blending combustion scheme is obtained through the benefit blending combustion model, the coal types to be purchased in the next month are coal type 1 and coal type 2, and parameters such as blending combustion proportion of three load intervals, heating value of coal entering into the furnace of the three load intervals and the like are obtained. And when the next month planned electric quantity is known and the starting and stopping conditions of each unit are predicted, the next month electric quantity of the first-stage unit and the second-stage unit can be calculated. The ratio of the high load, the medium load and the low load of the next month can be estimated according to the ratio of the high load, the medium load and the low load of each unit in the same period of the next month and the last year, so that the electric quantity Q of each load interval of the next month of the first-stage unit and the second-stage unit can be obtained_{Height 1}、Q_{In 1}、Q_{Low 1}、Q_{Height 2}、Q_{In 2}、Q_{Low 2}. The coal charge amount of each load interval A = Q × b × 7000/N/10^6, wherein Q is the power generation amount of each load interval, b is the power generation coal consumption of each load interval, N is the heating value of the coal charge, and N = KN_{Coal type 1}+（1-K）N_{Coal type 2}. The method comprises the steps that coal types to be distributed comprise coal types 1 and coal types 2, the amount of coal entering the furnace of the coal types 1 and 2 is determined according to the amount of coal entering the furnace A, the amount of coal entering the furnace A1= A x K of the coal type 1, and the amount of coal entering the furnace A2= A x (1-K) of the coal type 2, the coal types 1 in three load intervals and the coal amount of the coal type 2 are added respectively, and the coal amount of the coal type 1 and the coal type 2 to be purchased in the next month can be obtained, namely the coal type 1 and the A1 tons in the optimal co-firing scheme are purchased in the next month; the coal type is 2, A2 tons, so that the reference is provided for the purchase amount of the fire coal in the next month.

Referring to fig. 2, it is shown that the system for blending coal in a thermal power plant according to the present invention includes:

the proportioning module is used for determining the executing proportioning ratio of the coal blending combustion and is connected with the executing module;

the execution module is used for carrying out coal blending and burning according to each execution blending and burning ratio and a preset coal blending mode and is connected with the detection module;

the detection module is used for detecting the sulfur content and the load capacity in the waste gas and generating a corresponding detection result, and is connected with the adjustment module;

and the adjusting module is used for adjusting and correcting the executed combustion allocation ratio according to each detection result generated by the detecting module.

So far, the technical solutions of the present invention have been described in connection with the preferred embodiments shown in the drawings, but it is easily understood by those skilled in the art that the scope of the present invention is obviously not limited to these specific embodiments. Equivalent changes or substitutions of related technical features can be made by those skilled in the art without departing from the principle of the invention, and the technical scheme after the changes or substitutions can fall into the protection scope of the invention.

Claims (9)

1. A method for blending and burning coal in a thermal power plant is characterized by comprising the following steps:

step a, a proportioning module determines a plurality of selectable proportioning ratios according to the variety and the number of the coal types to be distributed and the allowed operating number of the coal mills;

b, the proportioning module determines the unit power supply cost of each alternative blending combustion ratio in a preset load interval according to the unit heating value and the standard coal unit price of each coal type to be distributed;

c, the proportioning module determines a plurality of preselected proportioning ratios in the preset load interval from the selectable proportioning ratios according to the maximum load capacity of the coal to be distributed under the selectable proportioning ratios and the sulfur content of the coal to be distributed;

d, the proportioning module determines the execution proportioning ratio in the load interval according to the unit power supply cost of each preselected proportioning ratio;

step e, the execution module carries out coal blending and burning according to each execution coal blending and burning ratio and a preset coal blending mode;

step f, detecting the sulfur content in the generated waste gas by a detection module after the time of mixed combustion T1 to generate a detection result, detecting the load capacity after the time of mixed combustion T2 to generate a detection result, and setting T1 to be less than T2;

step g, the adjusting module adjusts and corrects the executed blending combustion ratio according to each detection result generated by the detecting module;

in the step c, when the proportioning module selects the pre-selected proportioning ratio, the proportioning module selects the average sulfur content deltaS and the maximum load carrying capacity M of the coal in a single selectable proportioning ratio_{Maximum of}Respectively comparing the standard values with corresponding preset standard values, and judging according to comparison results:

when the delta S is less than or equal to the delta S1, judging that the optional blending ratio meets the requirement of sulfur content, and carrying out secondary judgment;

when Delta S is > [ Delta S1, judging that the optional burdening ratio can not be used as a pre-selected burdening ratio;

wherein, the Delta S1 is a preset standard value of sulfur content;

when the proportioning module carries out secondary judgment, M1 is set as a preset standard value of load carrying capacity,

when M is_{Maximum of}If the optional blending ratio is less than M1, judging that the optional blending ratio cannot be used as a pre-selected blending ratio;

when M is_{Maximum of}When the ratio is more than or equal to M1, the optional blending ratio is judged to be a pre-selected blending ratio;

in the step d, the load interval is determined after the load range of the generator set is divided according to a preset load limit value, the load interval comprises a high load interval, a medium load interval and a low load interval, when the proportioning module determines the executing proportioning ratio,

if the coal types to be distributed are a group, taking the preselected combustion ratio with the minimum unit power supply cost in the high load interval as the optimal combustion ratio of the high load interval, taking the preselected combustion ratio which is matched with the optimal combustion ratio of the high load interval and has the minimum unit power supply cost in the intermediate load interval as the optimal combustion ratio of the intermediate load interval, taking the preselected combustion ratio which is matched with the optimal combustion ratio of the high load interval and the optimal combustion ratio of the intermediate load interval and has the minimum unit power supply cost in the low load interval as the optimal combustion ratio of the low load interval, and taking the optimal combustion ratio of the high load interval, the optimal combustion ratio of the intermediate load interval and the optimal combustion ratio of the low load interval as the execution combustion ratio;

if the coal types to be distributed are more than one group, determining the comprehensive unit power supply cost of each group of coal types to be distributed according to the proportion of the generated energy of each load interval in the preset time length in the future and the unit power supply cost under each optimal distribution ratio corresponding to each group of coal types to be distributed, and determining each execution distribution ratio according to each optimal distribution ratio of the coal types to be distributed with the minimum comprehensive unit power supply cost or each optimal distribution ratio of the coal types to be distributed corresponding to a selection instruction input by a user;

step g1, when the adjusting module adjusts the executing proportioning ratio, the adjusting module compares the exhaust gas sulfur content Q detected by the detecting module with each preset exhaust gas sulfur content, and selects a corresponding proportioning adjusting coefficient according to the comparison result to adjust the executing proportioning ratio; step g2, when the adjusting module corrects the executing combustion mixture ratio, the adjusting module compares the load capacity M detected by the detecting module with each preset load capacity, and selects a corresponding mixture ratio correction coefficient according to the comparison result to correct the executing combustion mixture ratio; and g3, when the correction is completed, the adjusting module compares the proportion P' of the coal with the lowest sulfur content in the adjusted execution blending ratio with the proportion of the coal with the lowest sulfur content in each preset proportion, and selects corresponding blending compensation parameters according to the comparison result to compensate the execution blending ratio.

2. The method for blending coal in thermal power plant as claimed in claim 1, wherein in the step g1, when the adjusting module selects the ith preset blending ratio adjustment coefficient α i to adjust the blending combustion ratio, i =1,2,3 is set, the ratio of the coal with the lowest sulfur content in the adjusted blending combustion ratio is P ', and P' = P x α i is set, wherein P is the ratio of the coal with the lowest sulfur content in the blending combustion ratio, wherein,

when Q1 is more than or equal to Q < Q2, the adjusting module selects alpha 1 to adjust the executing proportioning firing ratio;

when Q2 is more than or equal to Q < Q3, the adjusting module selects alpha 2 to adjust the executing proportioning firing ratio;

when Q3 is not more than Q, the adjusting module selects alpha 3 to adjust the executing proportioning ratio;

wherein Q1 is the first preset exhaust gas sulfur content, Q2 is the second preset exhaust gas sulfur content, Q3 is the third preset exhaust gas sulfur content, Q1 is more than Q2 and more than Q3; alpha 1 is a first preset ratio adjusting coefficient, alpha 2 is a second preset ratio adjusting coefficient, alpha 3 is a third preset ratio adjusting coefficient, and alpha 1 is more than 1 and more than alpha 2 and more than alpha 3 and less than 2.

3. The method for blending coal in thermal power plant according to claim 2, wherein in the step g2, when the adjusting module selects the ith preset blending ratio correction coefficient β i to correct the executed blending ratio, i =1,2,3 is set, the percentage of the coal with the highest calorific value in the corrected executed blending ratio is R ', R' = R × β i is set, where R is the percentage of the coal with the highest calorific value in the executed blending ratio, and wherein,

when M1 is more than or equal to M < M2, the adjusting module selects beta 1 to correct the executed proportioning ratio;

when M2 is more than or equal to M < M3, the adjusting module selects beta 2 to correct the executed proportioning ratio;

when M3 is less than or equal to M, the adjusting module selects beta 3 to correct the executing combustion mixture ratio;

wherein M1 is a first preset load carrying capacity, M2 is a second preset load carrying capacity, M3 is a third preset load carrying capacity, M1 is more than M2 is more than M3; beta 1 is a first preset ratio correction coefficient, beta 2 is a second preset ratio correction coefficient, beta 3 is a third preset ratio correction coefficient, and beta 1 is more than 1 and more than beta 2 and more than beta 3 and less than 2;

in the step g3, when the adjusting module selects the i-th preset blending ratio compensation parameter θ i to compensate the executed blending ratio, i =1,2,3 is set, the percentage of the coal with the highest calorific value in the compensated executed blending ratio is R ", R" = R' × θ i is set, wherein,

when P' < P1, the adjusting module selects theta 1 to compensate the executed proportioning ratio;

when P1 is not less than P' < P2, the adjusting module selects theta 2 to compensate the executed proportioning ratio;

when P2 is not less than P' < P3, the adjusting module selects theta 3 to compensate the executed proportioning ratio;

wherein P1 is the coal proportion with the lowest first preset sulfur content, P2 is the coal proportion with the lowest second preset sulfur content, P3 is the coal proportion with the lowest third preset sulfur content, and P1 is more than P2 and more than P3; theta 1 is a first preset ratio compensation parameter, theta 2 is a second preset ratio compensation parameter, theta 3 is a third preset ratio compensation parameter, and theta 1 is more than 0 and more than theta 2 and more than theta 3 and less than 1.

4. The method for blending coal in thermal power plant according to claim 1, wherein in the step b, when the blending module determines the unit power supply cost,

the proportioning module determines the calorific value of the coal as fired corresponding to each selectable proportioning ratio according to the calorific value;

the proportioning module determines power supply coal consumption corresponding to each load interval according to each coal as fired calorific value;

the proportioning module determines the unit price of coal as fired corresponding to each optional proportioning ratio according to the unit price of the standard coal;

and the proportioning module determines the unit power supply cost according to the power supply coal consumption and the unit coal as fired unit price.

5. The coal blending method of the thermal power plant according to claim 4, wherein the calculation formula of the power supply coal consumption is as follows,

b_{for supplying to}=a₀+a₁M³+a₂M²+a₃M+a₄+b₁N²+b₂N+b₃

Wherein, b_{For supplying to}For the supply of power, a₀Rated load power supply coal consumption for units in the design of coal type for combustion, a₁、a₂、a₃、a₄For a first set of predetermined constants, b₁、b₂、b₃And the second group of preset constants, M is the unit load, and N is the calorific value of the coal as fired.

6. The method for blending coal in thermal power plant as claimed in claim 1, wherein in the step c, the proportioning module determines the pre-selected proportioning ratio,

determining the sulfur content of the coal as fired corresponding to each optional co-firing ratio according to the sulfur content;

and determining the selectable co-firing ratio of which the maximum load carrying capacity meets the load interval and the sulfur content of each coal as fired is less than or equal to a preset threshold value as the pre-selected co-firing ratio.

7. The method for blending coal in thermal power plant according to claim 6, wherein the maximum load carrying capacity is calculated by the formula,

M_{maximum of}=D×W/ b_{For supplying to}(1-n)×7000/ N/10^3

Wherein M is_{Maximum of}For the maximum load capacity, D is the maximum coal amount of a single mill, W is the number of running coal mills, b_{For supplying to}For supplying power and coal consumption, N is the plant power consumption rate of the unit, and N is the calorific value of coal as fired.

8. The method for blending coal in thermal power plant according to claim 1, wherein the calculation formula of the comprehensive unit power supply cost is as follows,

G_{synthesis of}=C_{Height of}×G_{Height of}+C_In×G_In+C_{Is low in}×G_{Is low in}

Wherein G is_{Synthesis of}Cost of power supply to said integrated unit, C_{Height of}Unit power supply cost, G, for optimal firing ratio in high load intervals_{Height of}Is the proportion of the power generation in the high load region, C_InUnit power supply cost, G, for optimal firing ratio between medium load regions_InIs the proportion of the power generation in the medium load region, C_{Is low in}Unit power supply cost, G, for optimal firing ratio in low load region_{Is low in}Is a proportion of the amount of power generation in the low load section.

9. A system for blending coal in a thermal power plant by using the method for blending coal in a thermal power plant according to any one of claims 1 to 8, comprising:

the proportioning module is used for determining the executing proportioning ratio of the coal blending combustion and is connected with the executing module;

the execution module is used for carrying out coal blending and burning according to each execution blending and burning ratio and a preset coal blending mode and is connected with the detection module;

the detection module is used for detecting the sulfur content and the load capacity in the waste gas and generating a corresponding detection result, and is connected with the adjustment module;

and the adjusting module is used for adjusting and correcting the executed combustion allocation ratio according to each detection result generated by the detecting module.

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